Using Systems of Equations.
Please help!!! I'm not sure what steps to do, to work this problem.

#7) Five hundred tickets were sold for a school play, which generated $3560 in revenue. The prices of the tickets were $5 for children, $7 for students, and $10 for adults. There were 180 more student tickets sold than adult tickets. Let x be the number of children tickets sold, let y be the number of student tickets sold, and let z be number of adult tickets sold. Find the number of each type of ticket sold.

Write a 3 by 3 system of equations to solve the problem stated above. Do not solve the system.

Equation 1: ______
Equation 2: ______
Equation 3: ______

(Write variable terms on the left-hand side each equation in aphabetical order. Write nonnegative constants on the right-hand side of each equation. Example: 3x-2y+z=20).